Calling the six-party talks "useless," the communist country vowed it would no longer be bound to any previous agreements and said it would restart nuclear plants that they had been disabling.

"We will actively consider building our own light-water nuclear reactor, will revive nuclear facilities, and reprocess used nuclear fuel rods," the statement said, referring to its plutonium-producing nuclear facilities at the Yongbyon complex near Pyongyang.

South Korean media reported it could take as little as three months to get the Yongbyon facilities up and running again. "The North definitely has enough plutonium to produce at least eight nuclear bombs," said Chang Yong-Seok, director of research at the Institute for Peace Affairs. "And now, they are hinting that enriched-uranium bombs will be next in the list, long term."

But analysts in Seoul said the bold language had been expected and should be regarded as diplomatic posturing in response to the Security Council's presidential statement.

"North Korea seems to be shocked," said Baek Seung-Joo, an analyst at the Korea Institute for Defense Analyses. "They were counting on China and Russia to be on their side, but they know that they have no other choice but to engage back into talks."

Analysts: Pyongyang's Bark Worse Than Its Bite

Baek said the North is using the U.N. Security Council censure as an excuse to get out of the six-party talks framework. For decades, Pyongyang has consistently demanded bilateral talks with the United States, but Washington has rejected the idea preferring to resolve the tensions on the Korean peninsula together with the neighboring countries.

"Compared to 2006, when they tested an underground nuclear bomb three months after launching seven missiles, this is not that serious," said Yun Duk-Min, professor at the Institute of Foreign Affairs and National Security. "This harsh talk is totally political for their domestic purposes. They need to whip up the country to make sure the people areloyal to Kim Jong-Il."

The six-party talks -- among the two Koreas, the U.S. China, Russia, and Japan -- are aimed at verifiable denuclearization of the Korean peninsula in return for as much as 1 million tons of fuel oil and other aid to the impoverished nation. The deal was finally reached in February 2007 after several years of excruciating diplomatic negotiations.

Last June, the North blew up the cooling tower in Yongbyon in full view of international media to symbolize its commitment to the talks. But the process has been in a deadlock over disagreement in how to verify the North's accounting of its previous nuclear activities.